Safety lowering device for tiltable x-ray table

ABSTRACT

An X-ray table having a hydraulic safety lowering device connected between a tiltable table body and a stationary base. Flow control means permits unrestricted fluid flow between opposite sides of a piston during upward movement of the platform, and provides restricted fluid flow during downward movement of the platform.

United States Patent [191 Yager et a].

[4 1 Apr. 16, 1974 SAFETY LOWERING DEVICE FOR TILTABLE X-RAY TABLE [75] Inventors: Norman J. Yager, Euclid; Warren A. Poole, South Russell; Timothy H. Arndt, Cleveland, all of Ohio [73] Assignee: Picker Corporation, Cleveland,

Ohio

[22] Filed: Sept. 14, 1971 [21] Appl. No.: 180,360

[52] US. Cl 250/439, 250/442, 269/323 [51] Int. Cl. H0lj 37/20 [58] Field of Search 250/55, 442, 439; 188/282,

[56] References Cited UNITED STATES PATENTS 3,043,953 7/1962 Craig et al. 250/55 Vassieck 188/282 Mayer 188/319 Primary Examiner-Archie R. Borchelt Assistant Examiner-B. Anderson Attorney, Agent, or firmer-Watts, Hoffmann, Fisher & Heinke [57] ABSTRACT An X-ray table having a hydraulic safety lowering device connected between a tiltable table body and a stationary base. Flow control means permits unrestricted fluid flow between opposite sides of a piston during upward movement of the platform, and provides restricted fluid flow during downward movement of the platform.

18 Claims, 4 Drawing Figures PATENTEDIFR is an 3805LO8O so I 1' a I l I 38 ml 32%' u.+- Y

INVENTORS WARREN A. POOLE 3 NORMAN JYAGER ,iifig. TIMOTHY H. ARNDT 2/642 Wmfiw mam ATTORNEYS SAFETY LOWERING DEVICE FOR TILTABLE X-RAY TABLE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to tiltable X-ray tables and more particularly to a safety device for slowly and safely lowering an X-ray table body if the tilt drive system fails with the table in an elevated position.

2. Prior Art Tiltable X-ray tables utilizing hydraulic systems are well known. However, for a variety of reasons they have enjoyed poor acceptance. One reason is that hydraulic systems tend to leak and the presence of hydraulic fluid on the floor of an X-ray room can be unsightly, unsanitary and dangerous. Other reasons are the complexity, the original and maintenance expense, and the difficulty in accomplishing tilting in both directions from the horizontal table with hydraulic systems. Accordingly electrically driven mechanical systems, are generally used for tilting the platform of the table relative to the base.

Among the mechanical drive systems commonly used, roller-chain drives have become popular clue to their simplicity, low cost and reliable nature. Despite the reliability of these roller-chain drive systems, there are occasionally failures such as the breakage of a chainor sprocket shaft. Such breadage may result in a sudden drop of the table body and its patient support surface to the horizontal position or below. This can be disquieting to a patient positioned on the table surface.

SUMMARY OF THE INVENTION The present invention provides a safety lowering device for slowly lowering an X-ray table body should the table tilt drive system fail. I v

A self-contained hydraulic safety device is provided which connects at one end to the base of the table and at the other end of the tiltable body. The safety device comprises a hydraulic cylinder having'a piston which is movable in a chamber in response to realtive movement between the base and the body.

Flow control means establishes fluid communication between opposite sides of the piston. A restricted flow passage formed through the piston is provided in parallel with a check valve. The check valve opens under fluid pressure when the body is moved upwardly, and closes when the body is moved downwardly. By this arrangement, both the check valve and the restricted flowpassage pass fluid when the body moves upwardly, but only the restricted flow passage passes fluid when the body moves downwardly.

The cylinder is positioned such that the piston rod extends substa'ntially vertically out on the top of the cylinder. Since the system is closed system, the only dynamic seal beyond which leakage out of the system can occur is at the top of the cylinder around the piston rod. Accordingly shouldany leakage occur in an older system it will tend to collect on the cylinder rather than dripping on the floor. Moreover, since the pressure of the hydraulic fluid is lower above the piston than below the piston, the possibility of leakage is minimized.

Accordingly, the primary object of the present invention is to provide an X-ray table with a novel and improved safety lowering device.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims taken in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an elevational view of a tiltable X-ray table employing a chain drive and including the safety lowering device of the present invention, the tiltable body of the table being shown in solid lines in the horizontal position and in phanton in the Trandelenburg position;

FIG. 2 is an elevational view similar to FIG. 1 but with the tiltable table body elevated to the vertical position;

FIG. 3 is an enlarged elevational view of the safety device of the present invention with portions thereof broken away to illustrate details; and,

FIG. 4 is an enlarged sectional view of a portion of the hydraulic safety device shown in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, an X-ray table is shown generally at 10. A stationary base or pedestal 11 supports a tiltable body 12. The body includes a patient support top T. The body 12 is pivotally connected to the pedestal 11 at 13 to permit movement of the platform relative to the base A fluoroscopic tower 14 is movably supported by the body 12. The tower 14 may include, in the usual fashion, a spot fllmer device '15. An X-ray tube (not shown) is carried by the tower and positioned within the body 12. v

A chain drive mechanism 20 is provided to tilt the body 12 from a position with the top T substantially horizontal, is shown in FIG. 1, to a position in which the top T is substantially vertical, as shown in FIG. 2. The table body shown in the drawing is also tiltable in the other direction to a so-called 15 Trandelenburg position, as shown in phantom in FIG. 1. The chain drive mechanism 20 includes a roller.chain 21 disposed along a substantially arcuate track and connected at opposite ends 22, 23 to portions of the body 12. At a point intermediate the ends 22, 23, the chain 21 is reeved around a drive sprocket 24. The drive sporcket is supported on a shaft carried within the base 11 and driven by means of a motor 25. By this arrangement, rotation of the drive sprocket 24 by the motor 25 will cause the chain 21 to move relative to the sprocket, whereby the body 12 will be caused to pivot about its connection 13 with the base '11.

While such a chain drive system is highly durable and reliable in operation, in accordance with the present invention, asafety device 30 is provided for slowly lowering the body 12 to the Trandelenburg position should the chain drive system break with the body in an elevated position. The safety device 30 comprises a hydraulic cylinder having its upper end pivotally connected to the platform at 31 and its lower end pivotally connected to the base at 32. I

Referring to FIG. 3, the hydraulic safety lowering device 30 is shown in greater detail. An elongated cylinder housing 33 defines a cylindrical chamber 34. A piston 35 is movable in the chamber 34. A piston rod 36 connects with the piston 35 at one end and at the other end with an apertured mounting flange 37.

The lower end of the housing 33 is closed by an end plate38. An apertured mounting flange 39 connects with the end plate 38. The upper end of the housing is closed by an apertured end plate 40. The piston rod 36 passes through the end plate 40. A fluid tight seal (not shown) is provided in the usual fashion between the end plate 40 and the piston rod 36.

A fluid reservior 42 communicates through a coupling 43 with the upper end of the chamber 34. The reservoir receives hydraulic fluid during the travel of the piston rod 36 into the chamber, since the fluid capacity of the chamber 34 is then decreased by the volume of the piston rod 36. A pressure gauge 44 also communicates with the chamber 34. The pressure gauge serves to provide an indication of the proper operation of the safety lowering device, as will be explained in greater detail. By this arrangement, fluid may be maintained within the chamber 34 and its pressure below the piston 35 monitored.

Referring to FIG. 4, the piston 35 is shown in greater detail. A pair of annular grooves 45, 46 are formed in the periphery of the piston 35. The grooves 45, 46 respectively carry O-rings 47, 48 to seal the region be? tween the housing 33 and the piston 35.

A centrally disposed axially extending bore 50 formed through the piston 35 receives the piston rod 36. Clamping means 51, 52 disposed on opposite sides of the piston 35 clamp the piston rod 36 into engagement with the piston 35. An annular groove 53 formed radially outwardly of the bore 50 receives an O-ring 54 for sealing the region between the piston 35 and the piston rod 36.

First and second passages 61, 62 are formed through the piston 35 to provide fluid flow communication between portions of the chamber 34 disposed on opposite sides of the piston. The first passage 61 has a portion of relatively narrow diameter which serves as a flow restriction passage. The second passage 62 is substantially larger in diameter at its most narrow point than the first passage 61. By this arrangement, the second passage 62 is adapted to provide a substantially unrestricted fluid flow between opposite sides of the piston 35. I

The lower end 68 of the passage 62 is enlarged and includes an annular radially extending seat 69. A check valve 70 is positioned within the enlarged portion 68. The check valve 70 includes a ball 71 which is biased into engagement with the seat 69 by a spring 72. A locking ring 73 supports the spring 72 and is, in turn, supported by engagement with a groove formed in the passage portion 68.

In operation, when the drive system tilts the body 12 upwardly away from the horizontal position, the piston rod 36 is caused to extend from the housing 33. The extension of the piston rod 36 moves the piston 35 upwardly causing the fluid in the region above the piston to be compressed. Compression of the fluid above the piston causes this fluid to exert a sufficient force on the upper side of the ball 71 to open the check valve 70. Hence, during the upward movement of the body 12, both the first and second passages 61, 62 pass fluid from the region above the piston to the region below 6 the piston. With both passages passing fluid in this fashion, the safety device 30 provides substantially no resistance to the upward travel of the body 12.

During downward movement of the body 12 from an elevated position, the check valve closes, thereby limiting the flow of fluid from opposite sides of the piston 35 to that which passes through the restricted passage 61. Such a restricted flow limits the descent of the platform to a relatively slow speed. During normal operation of the chain drive system, the platform is lowered at a slow speed which corresponds to the speed at which the safety device would alone lower the table. However, should the drive system break, the safety device will lower the body at the normal slow speed.

The pressure gauge 44 serves to indicate whether or not the fluid flow passages and the valve carried by the piston are operating properly. Should the check valve be lodged open, the pressure gauge 44 will register an improperly low pressure during descent of the body 12.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and thecombination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

What is claimed is:

1. An x-ray table comprising:

a. a base;

b. a tiltable body connected to the base and including a patient support;

0. drive means for tilting the body from a position wherein a supported patient is substantially horizontal to another position;

d. hydraulic safety device means which is auxiliary to the drive means and interconnects with the tiltable body and the base for slowly lowering said patient support should said drive means fail to support said patient support in an elevated position;

e. said safety device including a hydraulic cylinder defining a chamber having a piston movable therein, and flow control means establishing fluid communication between portions of said chamber disposed on opposite sides of said piston; and,

f. said flow control means being operable to provide restricted fluid flow between said portions when said patient support is moving downwardly;

g. whereby said restricted flow will assure the slow speed lowering of said patient support should said drive means fail.

2. The X-ray table of claim 1 wherein said fl'ow control means comprises a restricted flow passage carried by said piston.

3. The x-ray table of claim 1 wherein said flow control means is also operable to provide substantially unrestricted fluid flow between said portions when said patient support is moving upwardly.

4. The x-ray table of claim 3 wherein said flow control means comprises:

a. passage means establishing fluid communication between portions of said chamber disposed on opposite sides of said piston; and,

b. valve means for varying the fluid flow rate through said passage means from a substantially unrestricted fluid flow rate to a restricted fluid flow rate.

5. The x-ray table of claim 3 wherein:

said flow control means comprises first and second passages connected for parallel fluid flow;

said first passage includes flow restriction means disposed therein to provide a restricted fluid flow; and,

said second passage includes valve means for selectively opening and closing said second passage to permit substantially unrestricted fluid flow; whereby restricted fluid flow is provided between said portions of said chamber through said first passage when said valve means is closed, and substantially unrestricted fluid flow is provided by said second passage when said valve means is open.

The X-ray table of claim 5 wherein at least one of said passages is carried by said piston.

The x-ray table of claim 5 wherein said valve means comprises a check valve disposed to open under fluid pressure when said patient support is moved upwardly, and to close when said patient support is moved downwardly.

Th X-ray table of claim 7 wherein both of said passages are carried by said piston.

The x-ray table of claim 3 wherein said flow conthe base and the tiltable patient support of an x-ray table having a drive means for tilting the patient support from a position in which a supported patient is substantially horizontal to another position wherein portions of the patient support are elevated, said safety lowering device being auxiliary to the drive means and comprising:

hydraulic means including at least one chamber having a piston disposed therein, said piston being movable in said chamber;

. connection means adapted to connect said hydraulic means to the body and the base such that said piston will be caused to move in said chamber in response to relative movement between the patient support and the base;

. flow control means establishing fluid communication between portions of said chamber disposed on opposite sides of said piston;

said flow control means comprising passage means carried by said piston and including fluid pressure responsive valve means operable to provide substantially unrestricted fluid flow between said portions of said chamber during upward movement of said patient support and being operable to provide restricted fluid 'flow between said portions of said chamber during downward movement of said patient support.

11. The safety lowering device of claim 10 wherein said passage means comprises first and second passages connected for parallel fluid flow, and said means comprises a check valve disposed in one of said passages.

12. The safety lowering device of claim 11 wherein:

a. said frist passage comprises a relatively narrow portion for restricting fluid flow;

b. said second passage at its most narrow point is substantially larger than the narrow portion of said first passage thereby permitting a substantially unrestricted fluid flow; and,

c. said check valve is disposed in said second passage.

13. An x-ray table comprising:

a. a pedestal for mounting on a floor;

b. a patient support carried by the pedestal and including at least one surface for supporting a patient in a generally horizontal position;

c. drive means connected to an interposed between the pedestal and patient support for tilting the support from its horizontal position to a tilted position and return; and,

d. auxiliary safety means interposed between and connected to the patient support and the pedestal for permitting the drive means to tilt the patient support substantially without interference while preventing a sudden drop of the patient support and controlling the rate of descent of the patient support on failure of the drive means, whereby to minimize the possibility of injury to a supported patient if the patient support drops due to a drive means failure.

14. The x-ray table of claim 13 wherein:

a. said safety means includes a hydraulic cylinder defining a chamber having a piston movable therein, and flow control means establishing fluid communication between portions of said chamber disposed on opposite sides of said piston; and,

b. said flow control means being operable to provide restricted fluid flow between said portions when said patient support is moving downwardly;

c. whereby said restricted flow will assure the slow speed lowering of said patient support should said drive means fail.

15. The x-ray table of claim 14 wherein said flow control means comprises a restricted flow passage carried by said piston.

16. The x-ray table of claim 14 wherein said flow control means is also operable to provide substantially unrestricted fluid flow between said portions when said patient'support is moving upwardly.

17. The x-ray table of claim 16 wherein said flow control means comprises:

a. passage means establishing fluid communication between portions of said chamber disposed on opposite sides of said piston; and,

b. valve means for varying the fluid flow rate through said passage means from a substantially unrestricted fluid flow rate to a restricted fluid flow rate.

18. The x-ray table of claim 16 wherein:

a. said flow control means comprises first and second passages connected for parallel fluid flow;

b. said first passage includes flow restriction means disposed therein to provide a restricted fluid flow; and,

c. said second passage includes valve means for selectively opening and closing said second passage to permit substantially unrestricted fluid flow;

d. whereby restricted fluid flow is provided between said portions of said chamber through said first passage when said valve means is closed, and substantially unrestricted fluid flow is provided by said second passage when said valve means is open.

, April 16, 1974 Iiatent N Q- 1 080 Dated Inventor) Norman J. Yager et al It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

I Column 1, lineal, delete breadage" and substitute -b reakage I Column 1, line +6, delete "realtive and substitute relative Column 2 line 31, after the word 'base" insert In the Claims:

Column'S, line 21, delete "Th" andsubstitute The I Column 5, l ine 63, after the word "said" insert valve Column 6, line 1, delete "frist" and substitute first Signed and sealed this 8th day of October 1974 (SEAL) Attest:

McCOY M. GIBSON JR. Attesting Officer c. MARSHALL DANN Commissioner of Patents FORM PO-1050 (10-69) USCOMM-DC 60376-5 69 

1. An x-ray table comprising: a. a base; b. a tiltable body cOnnected to the base and including a patient support; c. drive means for tilting the body from a position wherein a supported patient is substantially horizontal to another position; d. hydraulic safety device means which is auxiliary to the drive means and interconnects with the tiltable body and the base for slowly lowering said patient support should said drive means fail to support said patient support in an elevated position; e. said safety device including a hydraulic cylinder defining a chamber having a piston movable therein, and flow control means establishing fluid communication between portions of said chamber disposed on opposite sides of said piston; and, f. said flow control means being operable to provide restricted fluid flow between said portions when said patient support is moving downwardly; g. whereby said restricted flow will assure the slow speed lowering of said patient support should said drive means fail.
 2. The X-ray table of claim 1 wherein said flow control means comprises a restricted flow passage carried by said piston.
 3. The x-ray table of claim 1 wherein said flow control means is also operable to provide substantially unrestricted fluid flow between said portions when said patient support is moving upwardly.
 4. The x-ray table of claim 3 wherein said flow control means comprises: a. passage means establishing fluid communication between portions of said chamber disposed on opposite sides of said piston; and, b. valve means for varying the fluid flow rate through said passage means from a substantially unrestricted fluid flow rate to a restricted fluid flow rate.
 5. The x-ray table of claim 3 wherein: a. said flow control means comprises first and second passages connected for parallel fluid flow; b. said first passage includes flow restriction means disposed therein to provide a restricted fluid flow; and, c. said second passage includes valve means for selectively opening and closing said second passage to permit substantially unrestricted fluid flow; d. whereby restricted fluid flow is provided between said portions of said chamber through said first passage when said valve means is closed, and substantially unrestricted fluid flow is provided by said second passage when said valve means is open.
 6. The X-ray table of claim 5 wherein at least one of said passages is carried by said piston.
 7. The x-ray table of claim 5 wherein said valve means comprises a check valve disposed to open under fluid pressure when said patient support is moved upwardly, and to close when said patient support is moved downwardly.
 8. Th X-ray table of claim 7 wherein both of said passages are carried by said piston.
 9. The x-ray table of claim 3 wherein said flow control means comprises a check valve disposed in a first passage communicating between opposite sides of said piston, and a second passage of a restricted character is provided in parallel with said first passage, whereby when said patient support moves upwardly, both of said passages transmit fluid, and when said patient support moves downwardly, only said second restricted passage transmits fluid between opposite sides of said piston.
 10. A safety lowering device for connection between the base and the tiltable patient support of an x-ray table having a drive means for tilting the patient support from a position in which a supported patient is substantially horizontal to another position wherein portions of the patient support are elevated, said safety lowering device being auxiliary to the drive means and comprising: a. hydraulic means including at least one chamber having a piston disposed therein, said piston being movable in said chamber; b. connection means adapted to connect said hydraulic means to the body and the base such that said piston will be caused to move in said chamber in response to relative movement between the patient support and the base; c. flow control means establishing fluid cOmmunication between portions of said chamber disposed on opposite sides of said piston; d. said flow control means comprising passage means carried by said piston and including fluid pressure responsive valve means operable to provide substantially unrestricted fluid flow between said portions of said chamber during upward movement of said patient support and being operable to provide restricted fluid flow between said portions of said chamber during downward movement of said patient support.
 11. The safety lowering device of claim 10 wherein said passage means comprises first and second passages connected for parallel fluid flow, and said means comprises a check valve disposed in one of said passages.
 12. The safety lowering device of claim 11 wherein: a. said frist passage comprises a relatively narrow portion for restricting fluid flow; b. said second passage at its most narrow point is substantially larger than the narrow portion of said first passage thereby permitting a substantially unrestricted fluid flow; and, c. said check valve is disposed in said second passage.
 13. An x-ray table comprising: a. a pedestal for mounting on a floor; b. a patient support carried by the pedestal and including at least one surface for supporting a patient in a generally horizontal position; c. drive means connected to an interposed between the pedestal and patient support for tilting the support from its horizontal position to a tilted position and return; and, d. auxiliary safety means interposed between and connected to the patient support and the pedestal for permitting the drive means to tilt the patient support substantially without interference while preventing a sudden drop of the patient support and controlling the rate of descent of the patient support on failure of the drive means, whereby to minimize the possibility of injury to a supported patient if the patient support drops due to a drive means failure.
 14. The x-ray table of claim 13 wherein: a. said safety means includes a hydraulic cylinder defining a chamber having a piston movable therein, and flow control means establishing fluid communication between portions of said chamber disposed on opposite sides of said piston; and, b. said flow control means being operable to provide restricted fluid flow between said portions when said patient support is moving downwardly; c. whereby said restricted flow will assure the slow speed lowering of said patient support should said drive means fail.
 15. The x-ray table of claim 14 wherein said flow control means comprises a restricted flow passage carried by said piston.
 16. The x-ray table of claim 14 wherein said flow control means is also operable to provide substantially unrestricted fluid flow between said portions when said patient support is moving upwardly.
 17. The x-ray table of claim 16 wherein said flow control means comprises: a. passage means establishing fluid communication between portions of said chamber disposed on opposite sides of said piston; and, b. valve means for varying the fluid flow rate through said passage means from a substantially unrestricted fluid flow rate to a restricted fluid flow rate.
 18. The x-ray table of claim 16 wherein: a. said flow control means comprises first and second passages connected for parallel fluid flow; b. said first passage includes flow restriction means disposed therein to provide a restricted fluid flow; and, c. said second passage includes valve means for selectively opening and closing said second passage to permit substantially unrestricted fluid flow; d. whereby restricted fluid flow is provided between said portions of said chamber through said first passage when said valve means is closed, and substantially unrestricted fluid flow is provided by said second passage when said valve means is open. 